Intimate partner violence (IPV) is a significant public health problem among adolescents and young adults. Approximately one-third of young people have experienced some form of violence by an intimate partner. There are short- and long-term consequences of IPV. Women in violent relationships experience higher rates of unintended pregnancy and sexually transmitted infections, women who become pregnant in violent relationships are more likely to die in childbirth, and children born into violent relationships hae higher rates of low birth weight and infant mortality. And, some research suggests that these health consequences are greater as the frequency and severity of violence increase. Although there have recently been significant advances in knowledge about IPV, methodological and substantive problems with past research substantially limit our understanding of IPV and how to reduce and prevent it. In particular, we know little about how IPV changes over time, and in particular, what individual and relationship factors influence these changes. We propose new research to investigate the dynamic patterns of violence within young women's intimate relationships and the extent to which individual and relationship factors influence these dynamic patterns. Such an investigation requires detailed, dynamic measures of IPV and a rich set of individual and relationship measures that are also dynamic across time. Most available data resources suffer from fundamental weaknesses for this purpose. Newly available, unique data from the Relationship Dynamics and Social Life (RDSL) study make this research possible because they feature detailed weekly measures of violence and pregnancy for a racially and socioeconomically diverse, population-representative random sample of young women. The specific aims of the project are to: (1) identify the dynamic patterns of violence within young women's intimate relationships and (2) investigate individual and relationship factors that influence the dynamic patterns of violence. To meet the specific aims of our research, we propose a study based on the analysis of existing data from the RDSL study, based on a sample of 1,003 18- and 19-year-old women in a Michigan county. Face-to-face, 60-minute interviews were followed by a 2.5 year journal-based weekly follow-up study about their relationship experiences (including violence), sex, contraception, and pregnancy.